Persistent Slabs
- Alta quota
- Limite del bosco
- Sotto il limite del bosco
- Probabilità
- Likely
- Dimensione
- 2–3
It could be easy to trigger a large avalanche up to 3’ on several layers of buried surface hoar. While we did not hear of any avalanches in Summit Lake yesterday the same dangerous snowpack setup exists that is responsible for several avalanches in Turnagain Pass. There were several remote triggered avalanches that occurred last weekend which is enough to be concerning. The most recent layer that was buried by the Thanksgiving Day storm is likely a widespread problem that was seen from the highway up to at least 2,300’ and probably higher meaning it could exist on many slopes.
Unfortunately, this type of problem doesn’t always give obvious clues in the field. It is notorious for allowing several tracks on a slope and then ripping out the whole slope. It can be triggered remotely meaning that you could be traveling on a low angle slope and trigger an avalanche above you. If you want to avoid this problem the safest option is to stick to low angle slopes with no steep faces above you. If you do decide to travel into avalanche terrain, be aware that areas that seem “safer” may be more dangerous than they usually are, and that there may be no warning signs that an instability is present. Also use safe travel techniques such as using safe zones and exposing one person at a time on a slope.
(11/22/2025)
Looking up at where I triggered the slope remotely on Tenderfoot.
Photo: Peter Wadsworth